For the first time, it has been demonstrated that a depression of mucociliary transport may occur upon an inhalation challenge with an antigen to a skin test positive animal independent of whether bronchoconstriction occurs. The response is not mediated by acetylcholine or histamine but appears to be related to SRS-A release. Adrenergic agonists speed up tracheal mucous transport and there appears to be a dose related effect. Freon propellant has no effect on transport of mucus. Measurement of tracheal mucous velocity in the past has been hampered by the invasiveness of the cinebronchofiberscopic method. By impregnating Teflon with bismuth trioxide, it is possible to visualize 1mm diameter Teflon discs with conventional image intensifier equipment. The discs can be blown into the trachea by means of a catheter or bronchofiberscope placed above the vocal cords. This less invasive approach makes the method satisfactory for repeated studies in normal subjects and patients with pulmonary disorders. BIBLIOGRAPHIC REFERENCE: Michaelson, E.D. and Serafini, S.M.: Quantitative differences in the cellular yield of two bronchial brushes, Am. Rev. Resp. Dis. 112: 267-268, 1975.